Controlling system for electrically operated lifts



April 19, 1938. N. c. SMART 2,114,506

CONTROLLING SYSTEM FOR ELECTRICALLY OPERATED LIFTS v 1 1 Flled Sept 17 936 4 Sheets Sheet Bela m i da! I I 83 DB E5 2c L5 ls x z 1 r 02 5 1 1 W ATTOk/Vfy April 1933- N. c. SMART 2,114,506

CONTROLLING SYSTEM FOR ELECTRICALLY OPERATED LIFTS Filed Sept. 17, 1936 4 Sheets-Sheet 2 M'erFoLwwJ April 19, 1938. N. 0. SMART 1 2,114,506

CONTROLLING SYSTEM FOR ELECTRICALLY OPERATED LIFTS Filed Sept. 1'7, 1936 4 Sheets-Sheet 3 c R 5 w x y 2 DA DB 52 Q d'bl 61 3 gig-- c' .3. an :1 21. F L

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CONTROLLING SYSTEM FOR ELECTRICALLY OPERATED LIFTS Fly. 2A

N. c. SMART 2,114,506

Filed Sept. 17, 1936 UA UB SF ST 4 Sheets-Sheet 4 Patented Apr. 19, 1938 UNITED STATES PATENT OFFICE CONTROLLING SYSTEM FOR ELECTRICALLY OPERATED LIFTS Application September 17, 1936, Serial No. 101,250 In Great Britain September 18, 1935 13 Claims.

This invention relates to control of a plurality of lifts situated contiguously and serving a plurality of floors. The aim of the invention is the direction of calls for the lifts in such a manner as to make the most eflicient use of the latter.

It has hitherto been known to arrange that a call made from a particular floor in a particular direction is directed by switching means to a lift in a favourable position to answer the call. By favourable is meant the lift which is near to and preferably travelling towards the floor from which the call is made; a still further preference is that the lift should be travelling in the direction in which the passenger intends to proceed.

Such systems are of considerable complexity, and hitherto involve the use of a quantity of apparatus per lift which varies proportionately both to the number of floors and to the number of lifts, i. e. if Q=the quantity of apparatus employed per lift, N=the number of floors, L=the number of lifts, then Q lcNL where k is a constant dependent on the type of system employed. As can easily be seen, these systems when applied to lifts of long travel, or large groupings, tend to possess an excessive quantity of switching apparatus which is not only costly but which leads to faulty operation owing to the increased chance of mechanical failure and circuit interruption through dirtying of contacts and the like. In addition, should-any portion. of the apparatus cease for any reason to function, the whole of the control system involving all the lifts is usually affected.

According, however, to the present invention, in a lift controlling system which caters for a plurality of lifts, one or more switching links are provided, each link comprising means for finding the location of an originating call, means for finding a lift in a suitable position or condition for answering the call, means for storing the call on apparatus individual to the selected lift, and means for intimating to the caller which lift to use.

In an embodiment of the present invention, one or more pairs of push buttons are provided at each floor served by a. group of lifts. A caller depresses one of a pair of buttons intimating an up or down call, this operation initiating movement of a step-by-step switch of a type used in telephone systems, which finds a lead characteristic of the floor from which the call is being made. When this lead is reached, the switch stops and a further switch commences stepping until it reached a point in its contact bank corresponding to the floor from which the call has been made. This second or lift allocating switch then proceeds to step further over leads connected to controlling mechanisms associated with lifts which are in a condition to answer the call. Indications of the position of each lift are afforded by means of a relay chain or switch which follows the position of the lift in the shaft, leads from the relay chain or switch being connected to the bank of the allocating switch.

Thus if an up call is made from floor 4, the first switch stops on a lead connected to floor 4, and the second switch, after stepping to a point corresponding to this floor, commences to look for a lift travelling upwards near or situated at floor 3, 2 or 1 in the order given. If no lift is found at any of these floors, a search can be made among lifts situated near to the originating floor. When a lift is found a relay characteristic of this lift is operated, contacts of this relay causing storage of the call to take place on a group of relays individual to the selected lift, the relay operated being decided by the position of the first switch.

At the same time, an indication is given by means of an illuminated announcement or the like to the caller intimating which lift is to be employed, the position at which the announcement is given and the number of the lift to be used being controlled by means of the above described switch link.

In order that the nature of the present invention may now be more clearly understood one arrangement in accordance with the invention will now be described by way of example with reference to the accompanying diagrammatic divorced contact drawings, of which Figures 1 and 1a show a general circuit diagram and Figures 2 and 2a. a code diagram to assist in the understanding of Figures 1 and 1a.

This circuit is adapted to distribute calls from any one of six floors, to any one of four lifts. Two call push buttons are provided at each floor, but for the sake of simplicity only the up call push buttons PA, PB, PC for floors 1, 2 and 3 respectively, are shown. The remaining three are wired in similar fashion, but are not shown. Depression of any one of these buttons operates one of the call storage relays FA-FC and sets in motion the switch PS.

This switch acts as a finder, and takes up a position corresponding to the floor at which the call button is pressed. The switch has a number of contact banks, these being in most cases interconnected with the contact banks of a further switch LS which acts to distribute stored calls to the lift most suitably positioned for answering them. Banks ES! and LS! are associated with the first lift, banks PS2 and LS2 with the second lift and so on. The connections from these latter banks shown bracketed are taken to the apparatus of the lift controlling systems of the second, third and fourth lifts, this apparatus being identical with that shown connected to banks FS! and LSi. As before stated the apparatus shown the figure is adapted to deal with up calls only, the buttons PAPC and the like being duplicated for down calls. These down call buttons act upon another similar apparatus group which distributes down calls, the only differen es being various reversals on the switch bank contacts so that the down calls are allotted to lifts occupyin positions suitable for answering down rather than up calls.

It is proposed to illustrate the operation of the system according to the invention by describing the effect of storing a call. This may be accomplished by depressing for example button PC, representing an up call at floor 3. This applies positive to relay PC which operates.

fcl locks relay FC operated to negative through the series resistance RC.

,702 prepares a releasing path for FC later.

fcs removes the positive from the fourth contact of bank PS5 and applies it to the first contact.

This latter positive is connected through the switch interrupter contacts is to the switch driving magnet FS and thence to negative via the low-resistance relay C. The relay C operates and the switch steps in known manner by selfinterruption, moving all its wipers over their associated contact banks. In the meantime, contact 01 holds relay ST operated, this relay being normally operated from positive on wiper FSG. All the contacts of relay ST are shown in their normal (operated) positions, this being indicated by an arrow on each contact.

When wiper FS5 reaches the second contact in its bank, it receives another pulse of positive potential from contact for so that the switch is stepped to the third and thence to the fourth contact by self-interruption. It then ceases to step, as positive has been removed from the fourth contact by fax. Since current no longer flows through relay C it releases and its contact 01 allows relay ST to release.

stl prepares an operating path for relay SF.

stz operates relay DA.

sis causes switch LS to commence stepping by self-interruption at its contact ls in known manner.

st; prepares an operating path for relay S.

dai operates relay DB.

The switch LS now impulses its wipers over their banks until wiper LS5 reaches the fourth contact, when positive derived from wiper PS6 and contact i of the associated bank is applied through wiper LS5 and contact 8151 to relay SF. This relay operates and its contact sfi locks it in this position.

This operation is performed for the purpose of enabling the switch LS to start searching for a lift in a suitable position to receive the call, from a point in its banks corresponding to the position from which the call was made. This searching or hunting action is performed over bank LSI and the corresponding banks LS2--LS4 associated with other lifts. As will be seen, the first half of the contact bank LSI and the like is connected in sequential manner to the contacts of bank MI, the contacts in the last half of bank LSI and the like being connected to the same contacts in MI, but in reverse sense.

This bank MI is part of a step-by-step switch which is individual to the lift. concerned, and which is impulsed backwards or forwards one step for every floor passed by the lift, either up or down. It is thus always in a'position corresponding to that occupied by the lift in the shaft. In addition to this bank, call storage relays UA, UB, US and the like are provided per lift, and operation of any one of these relays represents a call stored for a particular floor. The relays are each connected through locking contacts to bank FSI, and are operated from this bank, as will later be described. In addition, other contacts 3, 4 and 5 are provided per lift, contact 3 being moved from one side to the other in dependence on the direction of the motion of the lift, contact 5 being closed when the lift is stationary, while contact 4 is closed when the lift is in motion, as also is contact 6 when the lift is moving to a parking position. All these contacts are operated by control relays (not shown) individual to the lift concerned.

In addition, a tumbler switch ON is provided per lift, closure of which brings the lift into use. If the lift is not required for service this switch is opened, preventing storage of any calls for the particular lift with which it is associated.

Turning now to the matter of call distribution, and considering the case in hand, it will be remembered that the call stored is one on the third floor for an upward direction. Assuming that startings and reversals of direction are to be avoided if possible, then the most suitable lifts for answering this call are those which are at or near the third, second or first floors in the order given, and are travelling upwards or are stationary. The next most suitable lifts are those which are below the third floor and are moving downwards, and the most unsuitable are those which are above the third floor. The call is distributed to the most suitable lift as described below.

When wiper LS! and the similar wipers associated with the other lifts reach the fourth contacts in their banks and relay SF is operated, a negative potential is applied from contact Sf2 to one coil of each of the relays W, X, Y and Z. These relays are individual to the lifts with which each one is associated and further connections from the coils mentioned are taken to the apparatus shown, in each one of the separate lift controlling apparatus groups. Assuming that the call is to be taken by the first lift, i. e. the one associated with relay W, this potential is applied via the switch ON, contact 4, contact 3, wiper LSI and contact bank, to the bank Ml. As shown, the lift MI is standing at its lowest floor, and is moving away in a direction suitable for answering the call, so that contact 4 is closed, and contacts 5 and 6 are open. When wiper LSI reaches the 7th contact, the negative potential derived from sfz causes a current to flow through the relay W from the positive on wiper Ml, operating relay W. It should here be noted that similar conditions exist if the lift is below the call and is stationary, or if it is travelling to a parking position. Under these conditions contact 5 or contact 6 is closed, these short-circuiting the path via contacts 3 and 4, and enabling a call to be stored in the lift controlling apparatus if it is in either of these conditions.

101 breaks the self-interrupting circuit for the switch magnet LS and the switch ceases to step.

102 prepares an operating path for one of the call storage relays in the selected lift.

ws closes a circuit from negative on one coil of relay W via x2, 3 2, 22, stl, and coil of relay S to positive. Relay S operates and relay W remains operated.

s1 and 52 (see later).

s3 breaks the circuit of DA, but this relay, being slow to release, does not yet move its contacts.

.94 applies positive via we, FSI and the bank connections to relay UC, which operates and locks itself in this position to connections (not shown) in the individual lift apparatus. In addition, lamp GC is lighted.

s5, 36 and 87 are contacts which perform similar storage operations to the other lifts when required.

83 breaks the operating circuit from sf! of relay W, which does not yet release, being held operated over the path previously described.

After a short interval relay DA releases, and its contact don de-energizes relay DB which is also slow in releasing. When contact dbi closes on release of relay DB, positive from this contact is applied via contact .81, wiper FS5 and contact fez, this positive short circuiting relay FC, so that it releases. This cancels the call from the common storage group. In addition, positive is applied via contact 82 to the magnet FS and relay C which energizes both in series. The switch being of the reverse drive type does not yet step.

01 operates relay ST.

.9151 releases relay SF.

sti releases relay S and relay W.

in removes the short-circuiting potential from relay FC, enabling further calls to be stored in the common group.

.92 de-energizes the switch FS, enabling it to take a step. Relay C is de-energized, but being slightly slow to release does not open its contact 01 as yet.

a; removes positive from the indicating lamp GC which is extinguished.

If no further calls are stored the wiper PS5 now encounters positive potential on the contact on which it stands. It therefore steps by selfinterruption to the end of. the contact bank through the interrupter contacts fs until the switch reaches the position shown on the drawings. No positive is found on the first contact so that the switch stops. Positive is now applied to relay ST by wiper FS6 in the manner shown, so that release of relay C consequent on the deenergization of. the magnet circuit does not allow relay ST to release. The apparatus is now in a position to receive and distribute further calls.

From the foregoing it will be noticed that the call has been placed with a lift which is in a favourable position to receive it. In addition, an indication has been given by the lamp GC to the person storing the call as to the lift which he must take. A lamp similar to GC is provided at each floor foreach lift, these lamps being mounted near .the call originating push buttons. The intending lift user is instructed, therefore, to

watch which lamp lights after he has depressed the call button, this lamp telling him which lift is best adapted to answer his call. The operation of. the call storage relay associated with that particular lift ensures that it will be stopped at the required floor to pick up the passenger. Once the passenger is in the lift he issues instructions to the attendant or, in the case of a non-attended fully automatic lift, depresses a further call storage button intimating his destination.

Assuming that no lift exists in a position most suitable for answering a call, a search is made for lifts which are not so suitable. This is performed by connecting contacts 8I2 of bank LSI and similar banks in a reverse sense to bank Ml or the like, and by providing a relay R on bank LS5 which operates after the switch LS passes the half-way position, indicating that no lifts in an immediately favourable condition are available. Assuming that this is the case the switch LS5 commences to hunt over the second group of contacts, relay R being operated from positive derived from contact sfi. Contact r4 now being closed, provides an operating path for relay W through the switch ON if closed, this path bypassing all the relay contacts 3, 4, 5 or 6 of the lift in question. If no lifts exist below the call, the switch LS continues to step, and finally places the call in the next lift encountered irrespective of its position or condition. Thus a call, once stored, is not lost but is always delivered to a lift providing that the said lift is in service, i. c. has its tumbler switch ON closed.

One further condition remains to be described. If, as is quite possible, another call is stored whilst the link is dealing with a. first call, then at the conclusion of the distribution operation the switch FS commences to return as previously described to a normal position. If during this return motion its wiper FS5 encounters one of the contacts 2-'l on which no positive potential exists, i. e. in connection with which the associated call storage relay is operated, then its motion ceases, relay C releases followed by ST, and a further call allocating operation similar to that already described, ensues.

Although the circuit described caters for a relatively small number of lifts. and only one call storage operation at any one time, it would easily be possible to provide further links of the type shown, and allocate each call to a link for distribution to a suitable lift. Circuits of. the nature are well known in telephone practice, and would necessitate very little extra circuit complication.

As a still further variation, if the lifts are arranged to be controlled by a single button depression from each call, i. e. if the caller depresses a button which is not only characteristic of the floor at which he is situated, but also of the destination to which he wishes to be carried, the switches may be modified by addition of further banks so as not only to cause the selected lift to register a call for the floor at which the caller is situated, but also a call for the destination required. This action entails very little extra apparatus, and suitable connections are obvious to those skilled in the art. A system of this type is described, for example, in British patent specification No. 432,593.

I claim:

1. A lift system comprising a plurality of lifts serving a plurality of floors, call means at each floor, a call registering switch operable by the call means for registering a call from a floor, an allocating switch for selecting the lift most favorably situated for answering a call, lift relays arranged to be operated by-the allocating switch, call storage means for the respective lifts and circuits controlled by the respective lift relays for operating the call storage means of a lift selected by the allocating switch.

2. A lift system comprising a plurality of lifts serving a plurality of floors, call means at each floor, a call registering switch operable by the call means for registering a call from a floor, an allocating switch for selecting the lift most favorably situated for answering a call, call storage means for the respective lifts, relay means for operating the call storage means of a lift selected by the allocating switch and indicating means at each floor for the respective lifts arranged to be operated by said relay means for indicating at the calling floor the lift selected to answer the call.

3. A lift system as in claim 2 wherein said allocating switch has two series of operating contacts one arranged to operate in reverse order to the other.

4. A lift system comprising a plurality of lifts serving a plurality of floors, call means at each floor, a call registering switch operable by the call means to register a call from a. floor, lift following switches for the respective lifts, allocating switches having circuits for the respective lifts cooperating with lift following switches for selecting the lift to answer a call, call storage means for the respective lifts, relays and circuits controlled jointly by said call registering and allocating switches for operating the call storage means of the selected lift and indicating means operated and controlled by said relays for indieating at the calling floor the lift so selected.

5. A lift system as in claim 4 wherein there are provided relays and circuits controlled by said call registering switch so arranged that subsequent operation of the allocating switch for the actual selection of the lift to answer a call can take place only after said call registering switch has completed its registration of the call.

6. A lift system comprising a plurality of lifts serving a plurality of floors, call means at each floor, a call registering switch operable by the call means for registering a call from a floor, an allocating switch for selecting the lift to answer a call, relays and circuits controlled by the call registering switch of operating said allocating switch, the arrangement being such that said allocating switch is operated only after the call registering switch has registered acall, call storage means and indicating means for the respective lifts and relays and circuits controlled by said allocating switch for jointly operating the call storage and indicating means of the lift selected to answer a call.

7. A lift system as in claim 6 wherein lift position switches for the respective lifts arranged to be positioned according to the positions of the respective lifts are provided with circuits cooperating with said allocating switch, and relays controlled by said allocating switch are provided for selecting the lift to answer a call according to the respective positions of said lift position switches, the arrangement being such that the most available lift will be selected.

8. A lift system as in claim 6 wherein follower switches are provided for each lift cooperating with said allocating switch and the latter is provided with a double set of contacts for the follower switch of each lift, one set of contacts being used for selecting the most available lift.

9. A lift system comprising a plurality of lifts serving a plurality of floors, call means at each floor, a call registering stepping switch having wiper contacts corresponding to the floors served, circuit means controlled by said call means for stepping said switch to and stopping it at a contact corresponding to the floor of a call, an allocating stepping switch for selecting a lift to answer a call, the arrangement being such that thelift in'the most favorable position for answering the call is selected, call storage means for the respective lifts, relays and circuits controlled by said allocating switch for operating the call storage means of a selected lift and indicating means at each floor for the respective lifts arranged to be operated by said relays to indicate at the calling floor the lift selected to answer the call.

10. A lift system comprising a plurality of lifts serving a plurality of floors, call means at each floor, a call registering switch having stepping wipers cooperating with banks of contacts for each lift, each bank having contacts for each floor, circuit means controlled by the call means for operating the call registering switch and stepping its wipers to and stopping them on contacts corresponding to the floor of a call, call storage relays for the respective lifts having circuit connections tothe corresponding banks of contacts of the call registering switch, an allocating switch having stepping wipers cooperatingwith banks of contacts for each lift, lift follower wipers for the respective lifts cooperating with contacts for each floor, the latter contacts being connected to the corresponding contacts ofsaidallocating switch, relays and circuits controlled by. said call registering switch for operating said allocating switch after the call registering switch has been positioned to register a call, relays and circuits brought into action when the wiper of said allocating switch reaches contacts corresponding in position with the wipers of the call registering switch as positioned by a call for establishing circuits through the allocating switch contacts in cooperation with follower contacts of the respective lifts for hunting for an available lift and relays operated by the hunting circuits for completing operating circuits for the call storage relays of the respective lifts, the call storage relay so operated being determined by the floor call position of the call registering switch.

11. A lift system as in claim 10 wherein the circuit connections of the call storage relays are provided with branch circuits for lamps arranged to indicate at the calling poor the lift selected when the corresponding call storage relay is operated.

12. A lift system as in claim 10 wherein the circuits .and relays cooperating with the respective follower switches and the allocating switch are arranged to select as the first selection of a lift to answer a call the nearest available lift in position to or moving in the direction of the call.

13. A lift system as in claim 10 wherein there are provided additional circuits and relays arranged to cooperate with said allocating switch for selecting as the lift to answer a call, a lift positioned or moving in the opposite direction from the direction of the call.

NORMAN CAROL SMART. 

